In other species: domestic cat , dog , pig

Possibly relevant human trait(s) and/or gene(s)s (MIM numbers): 306900 (trait) , 300746 (gene)

Mendelian trait/disorder: unknown

Considered a defect: yes

Cross-species summary: Also called factor IX deficiency or Christmas disease. This is one of the two X-linked bleeding disorders, haemophilia A being the other. The fact that these two disorders are X-linked in all species reported to date provides strong support for Ohno's suggestion that the X chromosome has been highly conserved throughout evolution.